How to Build Trailers

A trailer is a type of cart that hitches to the back of a vehicle and is used to transport large items such as automobiles, furniture, landscaping equipment and more. There are many different types of trailers, from enclosed trailers used to carry animals to v-shaped, custom trailers used to carry boats, but the basic trailer design concept is the same for any type of trailer. Trailers can be bought for thousands of dollars, but if you want to, you can save a lot of money by making your own. Follow these steps for how to build a trailer.


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    Find axles. You may use 1 axle or 2, but it is recommended that you use 2, as 2 axles will carry the most weight and give you the best shock absorption. You have some choices when it comes to searching for axles for custom trailers, so keep the following things in mind:
    • A junkyard is a great place to find inexpensive axles.
    • You can make a trailer out of old truck axles or mobile home axles.
    • The axles you choose should have springs and brakes.
    • When shopping for axles, keep in mind that you will want to build a trailer that is approximately 100 inches (254 cm) wide. If you buy axles that are wider than that, you will need to cut out the middle section of them and weld them back together, to the appropriate dimension.
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    Buy wheels, if your axles did not come with them. Use only tires specifically made for trailers. They should be 15 inches (38 cm) wide and made of bias-ply nylon.
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    Build a trailer frame. Use 4 inch (10.16 cm) by 4 inch (10.16 cm) steel bars.
    • Weld sections of steel bar together to make a rectangular frame in the size you desire.
      Image titled Build Trailers Step 3Bullet1
    • Verify that the frame is a perfect rectangle by checking the corner angles and the cross measurements from one end to the other.
    • Cut 5 steel bars to the width of the frame using a chop saw with a blade specifically made for cutting metal.
    • Lay the axles underneath the frame for reference. They should be 16 inches (40.6 cm) past the center mark, toward the end of the trailer.
    • Weld the width bars to the frame to provide stability. Start with the center bar, which should be placed in the middle of the 2 axles. Weld the next 2 bars at either end. The remaining 2 should be welded at the spring hanger mounting points.
      Image titled Build Trailers Step 3Bullet5
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    Make a trailer tongue. Use 4 inch (10.16 cm) by 4 inch (10.16 cm) steel bars.
    • Use the chop saw to cut 2 41 inch (104 cm) lengths of steel bar.
    • Position the steel bars so that half of them lie underneath the frame and the other half of the extends out the front of the frame.
    • Weld them to the front of the trailer frame, 1 on each side, angling them so that their ends meet, forming a triangle.
    • Use the chop saw to cut the tips where the steel bars meet, at the front of the trailer, and weld them together.
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    Weld a hitch that is compatible with the vehicle you will use for towing to the tongue of your trailer, where the 2 tips meet.
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    Attach the axles.
    • Flip the trailer frame over so that its underside is facing up.
    • Lay the 2 axles on the underside of the frame, lining them up so that they are on either side of the center crossbar of the trailer frame.
    • Weld the spring hangers of the axles to the frame.
    • Flip the trailer over and finish welding the axles on from the top of the frame.
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    Cover the frame with heavy gauge metal plates cut to size and weld them in place.


  • Check with your local motor vehicle regulatory agency to make sure it is legal to convert used truck or mobile home axles before you build a trailer out of them.
  • Although you can make sturdy and reliable custom trailers out of used parts, it is advisable to purchase new tires, as you want to do everything you can to avoid any blow outs down the line.
  • Brake lights are necessary to keep custom trailers street legal. You can purchase a taillight kit at any local auto parts store.
  • Always use a welding mask while you are welding.


  • When purchasing your trailer tires, don't forget a spare.

Things You'll Need

  • Measuring tape
  • Axle(s)
  • 4 inch (10.16 cm) by 4 inch (10.16 cm) steel bars
  • Welder
  • Welding mask
  • Trailer hitch
  • Right angle
  • Heavy gauge metal sheets
  • Chop saw

Article Info

Categories: Landscaping and Outdoor Building